Mass spectrometry provides a rapid and sensitive technique for the determination of the molecular mass of a molecule or mixture of molecules. In the analysis of peptides and proteins, mass spectrometry can provide detailed information regarding, for example, the molecular mass (also referred to as “molecular weight” or “MW”) of the original molecule, the molecular masses of peptides generated by proteolytic digestion of the original molecule, the molecular masses of fragments generated during the ionization of the original molecule, and even peptide sequence information for the original molecule and fragments thereof. Mass spectrometers are extremely precise; their performance and calibration must be carefully monitored as systematic errors may cause erroneous m/z values or changes in sensitivity. Methods and kits for the calibration of mass spectrometers have been described in various patents and applications (See, e.g., U.S. Pat. No. 4,847,493; U.S. Patent Application Publication No. 2002/0033447; U.S. Patent Application Publication No. 2002/0045269; U.S. Patent Application Publication No. 2003/0062473) and are also commercially available (See, e.g., PROTEOMASS Peptide and Protein MALDI-MS Calibration Kit (Sigma-Aldrich, St. Louis, Mo., USA); Mass Standards Kit (Applied Biosystems, Foster City, Calif., USA); MASSPREP reference standards (Waters, Milford, Mass., USA); Protein Calibration Standard 120,000-70,000 Da (Bruker Daltonics, Billerica, Mass., USA); All-in-1 Protein Standard (Ciphergen, Fremont, Calif., USA)). However, these kits do not directly provide a measure of instrument sensitivity or dynamic range in a single run.